Question

Whyyyy fountain pens leaks at higher altitude

Answer 1

A fountain pen leaks at higher altitude because the air pressure inside the ink tube of pen is higher than the air pressure outside when we breath in our ribs move outward our diaphragm moves down. The volume of the cest cavity increases and inside is spread over a large space.

Answer 2

The pressure at higher altitude is comparatively less, so to equalize the pressure difference ink starts moving out from pen which has a relative high pressure